Ever heard of the whale that speaks human? Meet NOC, a white beluga whale
that "talks" just like you and me:

For years, NOC was part of the U.S. Navy's Marine Mammal Program in
San Diego, which was aimed at studying whether whales, dolphins, seals
and other marine mammals could do underwater reconnaissance or perhaps
even disable mines. NOC was captured in 1977 in Canada's Hudson Bay
and brought down to California to work with researchers and divers.
(He was the smallest of the pack, and Ridgway says that led to the nickname
"no-see-um," or NO-C for short.)

Seven years later, the researchers noticed that NOC spontaneously
started making unusual sounds — "as if two people were conversing
in the distance just out of range for our understanding," they
reported in the journal Current Biology. One time, a diver came to the
surface outside NOC's enclosure and asked his colleagues, "Who
told me to get out?" They soon concluded it was the whale, which
must have been saying "Out, out, out."